In the case of known gantry-type washing installations with two gantries which may be separately movable or may be coupled together (cf. DE 36 16 817 C1), in general a horizontal brush and a pair of vertical brushes are located on each of the two gantries. These gantry-type washing installations, which are designed for a high hourly vehicle throughput, need, however, a relatively large amount of space, for in addition to the length of the vehicle, a holding space corresponding to the length of the two gantries is required in front of or behind the vehicle. Because of the large space requirement, the known gantry-type washing installations with two gantries are not suitable for installation in the petrol companies' standard washing bays. Although gantry-type washing installations with only one gantry need less space, they have a low washing capacity.
The object of the invention is therefore to provide a method and also a gantry-type washing installation for washing motor vehicles of the above-mentioned kind which require less space than known gantry-type washing installations with two gantries, but enable a high vehicle throughput.
Proceeding from a method of the above-mentioned kind, the method as per the invention is characterised in that washing is performed, apart from the two horizontal brushes, with a single pair of vertical brushes which wash between the two horizontal brushes and are located on one of the two gantries, that during a forward movement of the gantries the washing process is commenced with the first horizontal brush in the front third of the vehicle, while the nose is washed with the two vertical brushes, that then the nose and the top of the vehicle approximately up to the rear third of the vehicle are washed with the second horizontal brush, that the direction of travel of the gantries is reversed as soon as the tail wash has been executed with the two vertical brushes and before the second horizontal brush has reached the tail of the vehicle, that during the return movement of the two gantries washing with the brushes is continued until the vertical brushes have passed the nose of the vehicle and that the first gantry is then stopped while the first horizontal brush is still in the area above the first third of the vehicle.
Proceeding from a gantry-type washing installation for vehicles of the above-mentioned kind, the invention provides that the gantry-type washing installation includes a single pair of vertical brushes which are located between the two horizontal brushes on one of the two gantries and that the gantry-type washing installation comprises a control device which switches the gantries from forward to return movement before the second horizontal brush has reached the tail of the vehicle and which terminates the return movement of the gantries as soon as the vertical brushes have passed the nose of the vehicle and the first horizontal brush is still in the area above the first third of the vehicle.
The invention is therefore based on the idea that during both the forward movement and the return movement of the gantries, the two gantries are not moved beyond the full length of the vehicle, but each gantry movement is terminated when one of the two roof brushes is still in the area above the front or, respectively, rear third of the vehicle. By this means and through the use of only one pair of vertical brushes located between the horizontal brushes, the gantry-type washing installation requires, in addition to the length of the vehicle, only the installed length of a single gantry in front of and behind the vehicle. The method as per the invention can therefore be executed, and the gantry-type washing installation as per the invention erected, in the petrol companies' standard washing bays, in which there is otherwise only enough space for a gantry-type washing installation with a single gantry.
As the washing operation is commenced with the first horizontal brush while it is already in the region of the front third of the vehicle approximately in the middle of the bonnet, as the direction of travel of the gantries is reversed before the second horizontal brush has reached the tail of the vehicle, and as during the return movement of the gantries the first gantry is stopped while the first horizontal brush is still in the region above the first third of the vehicle, a considerable shortening of the gantries' travelling distances is achieved, leading to a shortening of the washing time and hence a higher hourly vehicle throughput.